Chapter IX: Introduction (2)

Inasmuch as the earth is not precisely spherical, but is slightly flattened at the poles, successive degrees of latitude are not absolutely uniform all along a meridian, but decrease slightly as the poles are approached. The deviation is so slight, however, that for practical purposes the degree of latitude may be considered as an unvarying unit. But obviously such is not the case with a degree of longitude. The most casual glance at a globe on which the meridian lines are drawn, shows that these lines intersect at the poles, and that the distance between them is, in the nature of the case, different at each successive point between poles and equator. It is only at the equator itself that a degree of longitude represents 1/360 of the earth's circumference. Everywhere else the parallels of latitude cut the meridians in what are termed small circles--that is to say, circles that do not represent circumference lines in the plane of the earth's center. Therefore while all points on any given meridian of longitude are equally distant in terms of degrees and minutes of arc from the meridian of Greenwich, the actual distances from that meridian of the different points as measured in miles will depend entirely upon their latitude.

At the equator each degree of longitude corresponds to (approximately) sixty miles, but in the middle latitudes traversed for example by the transatlantic lines, a degree of longitude represents only half that distance; and in the far North the meridians of longitude draw closer and closer together until they finally converge, and at the poles all longitudes are one.

It follows, then, that the navigator must always know both his latitude and his longitude in order to estimate the exact distance he has sailed. We have seen that a single instrument, the sextant, enables him to make the observations from which both these essentials can be determined. We must now make further inquiry as to the all important guide without the aid of which his observations, however accurately made, would avail him little. This guide, as already pointed out, is found in the set of tables known as the _Nautical Almanac_.

THE NAUTICAL ALMANAC

Had the earth chanced to be poised in space with its axis exactly at right angles to its plane of revolution, many computations of the astronomer would be greatly simplified. Again, were the planetary course circular instead of elliptical, and were the earth subject to no gravitational influences except that of the sun and moon, matters of astronomical computation would be quite different from what they are. But as the case stands, the axis of the earth is not only tipped at an angle of about twenty-three degrees, but is subject to sundry variations, due to the wobbling of the great top as it whirls.

Then the other planets, notably the massive Jupiter, exert a perverting influence which constantly interferes with the regular progression of the earth in its annual tour about the sun. A moment's reflection makes it clear that the gravitation pull of Jupiter is exerted sometimes in opposition to that of the sun, whereas at other times it is applied in aid of the sun, and yet again at various angles. In short, on no two successive days--for that matter no two successive hours or minutes--is the perturbing influence of Jupiter precisely the same.

What applies to the earth applies also, of course, to the varying action of Jupiter on the moon and to the incessantly varied action of the moon itself upon the earth. All in all, then, the course of our globe is by no means a stable and uniform one; though it should be understood that the perturbations are at most very slight indeed as compared with the major motions that constitute its regular action and lead to the chief phenomena of day and night and the succession of the seasons.

Relatively slight though the perturbations may be, however, they are sufficient to make noteworthy changes in the apparent position of the sun and moon as viewed with modern astronomical instruments; and they can by no means be ignored by the navigator who will determine the position of his ship within safe limits of error. And so it has been the work of the practical astronomers to record thousands on thousands of observations, giving with precise accuracy the location of sun, moon, planets, and various stars at given times; and these observations have furnished the basis for the elaborate calculations of the mathematical astronomers upon which the tables are based that in their final form make up the _Nautical Almanac_, to which we have already more than once referred.

These calculations take into account the precise nature of the perturbing influences that are exerted on the earth and on the moon on any given day, and hence lead to the accurate prediction as to the exact relative positions of these bodies on that day. Stated otherwise, they show the precise position in the heavens which will be held at any given time by the sun for example, or by the important planets, as viewed from the earth. How elaborate these computations are may be inferred from the statement that the late Professor Simon Newcomb used about fifty thousand separate and distinct observations in preparing his tables of the sun. Once calculated, however, these tables of Professor Newcomb are so comprehensive as to supply data from which the exact position of the sun can be found for any day between the years 1200 B.C. and 2300 A.D., a stretch of some thirty-five centuries.

Such a statement makes it clear how very crude and vague the deductions must have been from the observations of navigators, however accurately made, prior to the time when such tables as those of the _Nautical Almanac_ had been prepared. Fully to appreciate this, it is necessary to understand that the observations supplied in such profusion for the use of the mathematical astronomer are in themselves subject to errors that might seriously vitiate the results of the final computation. They must, therefore, be made with the utmost accuracy, and with instruments specially prepared for the purpose. The chief of these instruments is not the gigantic telescope but the small and relatively simple apparatus known as a transit instrument. This constitutes essentially a small telescope poised on very carefully adjusted trunnions, in such a way that it revolves in a vertical axis, bringing into view any celestial body that is exactly on the meridian, and bodies in this position only. To make observation of the transit--that is to say the passage across the meridian line--of any given body more accurate, the transit instrument has stretched vertically across the center of its field of vision a spider web, or a series of parallel spider webs; in order, in the latter case, that the mean time of several observations may be taken.

So exceedingly difficult is it to manufacture and mount an instrument of requisite nicety of adjustment, that the effort has almost baffled the ingenuity of the mechanic. Sir George Airy, in making a transit instrument for use at the Royal Observatory at Greenwich, required the trunnions on which it was to be mounted to be ground truly cylindrical in form within a variation of one thirty-two-thousandth of an inch as determined by a delicate spirit level. Even when all but absolute decision has been obtained, however, it is quite impossible to maintain it, as the slightest variation of temperature--due perhaps to the application of the hand to one of the pillars on which the trunnions rest--may disturb the precise direction of the spider webs and so militate against absolute accuracy of observation. The instrument must, therefore, be constantly tested and its exact range of errors noted and allowed for.

To devote so much labor to details, merely in the effort to determine the precise moment at which a star or planet crosses the meridian, would seem to be an absurd magnification of trifles. But when we reflect that the prime object of such observations is to supply practical data which will be of service in enabling navigators on all the seas of the globe to bring their ships safely to port, the matter takes on quite another aspect. We have here, obviously, another and a very striking illustration of the close relationship that obtains between the work of the theoretical devotee of science and that of the practical man of affairs.

SOUNDINGS AND CHARTS

Though the navigator, thanks to his compass, sextant, and _Nautical Almanac_, may determine with a high degree of precision his exact location, yet even the best observations do not enable him to approach a coast without safeguarding his ship by the use of another piece of mechanism calculated to test the depth of the waters in which he finds himself at any given moment. In its most primitive form--in which form, by the bye, it is still almost universally employed--this apparatus is called the lead,--so called with much propriety because it consists essentially of a lump of lead or other heavy weight attached to a small rope. Knots in the rope enable the sailor who manipulates the lead to note at a glance the depth to which it sinks. Most ocean travelers have seen a sailor heaving the lead repeatedly at the side of the ship and noting the depth of the water, particularly as the ship approached the Long Island shore.

While this simple form of lead suffices for ordinary purposes, when the chief information sought is as to whether the water is deeper than the draft of the ship, it is at best only a rough and ready means of testing the depth in relatively shallow waters. For deeper waters and to test with greater accuracy the depths of uncharted regions, and in particular to determine the character of the sea bottom at any given place, more elaborate apparatuses are employed. One of the most useful of these is the invention of the late Lord Kelvin. In this the lead is replaced by a cannon ball, perforated and containing a cylinder which is detached when the weight reaches the bottom and is drawn to the surface filled with sand or mud, the cannon ball remaining at the bottom. In another form of patent lead, a float becomes detached so soon as the weight strikes the bottom and comes at once to the surface, thus recording the fact that the bottom has been reached,--a fact not always easy to appreciate by the mere feel of the line when the water is fairly deep.

It is obvious that however well informed the navigator may be as to his precise latitude and longitude, he can feel no safety unless he is equally well informed as to the depth of the water, the proximity of land, the presence or absence of shallows in the region, and the like. He must, therefore, as a matter of course, be provided with maps and charts on which these things are recorded. From the days when navigation first became a science, unceasing efforts have been made to provide such maps and charts for every known portion of the globe. Geographical surveys, with the aid of the method of triangulation, have been made along all coasts, and elaborate series of soundings taken for a long distance from the coast line, and there are now few regions into which a ship ordinarily sails, or is likely to be carried by accident, for which elaborate charts, both of coast lines and of soundings, have not been provided. The experienced navigator is able to direct his ship with safety along coasts that he visits for the first time, or to enter any important harbor on the globe without requiring the services of a local pilot,--albeit the desire to take no undue risk makes it usual to accept such services.

Time was, however, when maps and charts were not to be had, and when in consequence the navigator who started on his voyages of exploration was undertaking a feat never free from hazard. Until the time of Mercator there was not even uniformity of method among map makers in the charting of regions that had been explored. The thing seems simple enough now, thanks to the maps with which every one has been familiar since childhood. But it required no small exercise of ingenuity to devise a reasonably satisfactory method of representing on a flat surface regions that in reality are distributed over the surface of a globe. The method devised by Mercator, and which, as everyone knows, is now universally adopted, consists in drawing the meridians as parallel lines, giving therefore a most distorted presentation of the globe, in which the distance between the meridians at the poles--where in reality there is no distance at all--is precisely as great as at the equator. To make amends for this distortion, the parallels of latitude are not drawn equidistant, as in reality they practically are on the globe, but are spaced farther and farther apart, as we advance from the equator toward either pole. The net result is that an island in the arctic region would be represented on the map several times as large as an island actually the same size but located near the equator. Doubtless most of us habitually conceive Alaska and Greenland to be vastly more extensive regions than they really are, because of our familiarity with maps showing this so-called "Mercator's projection."

Of course maps are also made that hold to the true proportions, representing the lines of latitude as equidistant and the meridians of longitude as lines converging to a point at the poles. But while such a map as this has certain advantages--giving, for example, a correct notion of the relative sizes of polar and other land masses--it is otherwise confusing inasmuch as places that really lie directly in the north and south line cannot be so represented except just at the middle of the map, and it is very difficult for the ordinary user of the map to gain a clear notion as to the actual points of the compass. A satisfactory compromise may be effected, however, by using Mercator's projection for maps showing wide areas, while the other method is employed for local maps.

THE LURE OF THE UNKNOWN

While the average man, even with well developed traveling instincts, would perhaps prefer always to feel that he is sailing in well charted waters and along carefully surveyed coasts, there have been in every generation men who delighted in taking risks, and for whom half the charm of a voyage must always lie in its dangers. Such men have been the pioneers in exploring the new regions of the globe. That there was no dearth of such restless spirits in classical times and even in the dark ages, records that have come down to us sufficiently attest. For the most part, however, their names have not been preserved to us. But since the ushering in of the period which we to-day think of as the beginning of modern times, records have been kept of all important voyages of discovery, and at least the main outlines of the story of the conquest of the zones are familiar to everyone.

Some of the earliest explorers, most notable among whom was the Italian Marco Polo, traveled eastward from the Mediterranean and hence journeyed largely by land. But soon afterward, thanks to the introduction of the compass,--which instrument Marco Polo has sometimes been mistakenly accredited with bringing from the East,--the adventurers began to cast longing eyes out toward the western horizons. Among the first conspicuous and inspiriting results were the discoveries of the groups of islands known as the Cape Verdes and the Azores. The Canary Islands were visited by Spaniards even earlier, and became the subject of controversy with the other chief maritime nation of the period, the Portuguese.

When the controversy was adjusted the Spaniards were left in possession of the Canaries, but the Portuguese were given by treaty the exclusive right to explore the coast of Africa. Following up sundry tentative efforts, the daring Portuguese navigator, Bartholomeo Dias, in the year 1487, passed to the southern-most extremity of Africa, which he christened the Cape of Good Hope. At last, then, it had been shown that Africa did not offer an interminable barrier to the passage to the fabled land of treasures in the East. Before anyone had ventured to follow out the clues which the discovery of the Cape had presented, however, Columbus had seemingly solved the problem in another way by sailing out boldly into the West and supposedly coming to the East Indies in 1492.

The western route was barred to the Portuguese but the eastern one remained open to them, and before the close of the century Vasco da Gama had set out on the voyage that ultimately led him to India by way of the Cape (1497-1500 A.D.). Twenty years later another Portuguese navigator, Magellan by name, started on what must ever remain the most memorable of voyages, save only that of Columbus. Magellan rounded the southern point of South America and in 1521 reached the Philippines, where he died. His companions continued the voyage and accomplished ultimately the circumnavigation of the globe; and in so doing afforded the first unequivocal practical demonstration, of a character calculated to appeal to the generality of uncultured men of the time, that the world is actually round.

Two routes from Europe to the Indies had thus been established, but both of them were open to the objection that they necessitated long detours to the South. To the geographers of the time it seemed more than probable that a shorter route could be established by sailing northward and coasting along the shores either of Europe to the East or--what seemed more probable--of America to the West. Toward the close of the sixteenth century the ships of the Dutch navigators had penetrated to Nova Zembla, and a few years later Henry Hudson visited Spitzbergen, thus inaugurating the long series of arctic expeditions. Then Hudson, still sailing under the Dutch flag, made heroic efforts to find the fabled northwest passage, only to meet his doom in the region of the Bay that has since borne his name.

THE QUEST OF THE POLE

This was in the year 1610. For long generations thereafter successors of Hudson were to keep up the futile quest; and when finally it had been clearly established that no northwest passage to the Pacific could be made available, owing to the climate, the zest for arctic exploration did not abate, but its goal was changed from the hypothetical northwest passage to the geographical pole.

Henry Hudson had in his day established a farthest North record of about the eighty-second parallel of latitude--leaving only about five hundred miles to be traversed. But three centuries were required in which to compass this relatively small gap. Expedition after expedition penetrated as far as human endurance under given conditions could carry it. Some of the explorers returned with vivid tales of the rigors of the arctic climate; others fell victim to conditions that they could not overcome. But the seventeenth, eighteenth, and nineteenth centuries passed and left the "Boreal Center" undiscovered.

Toward the close of the nineteenth century the efforts of explorers seemed to be redoubled and one famous expedition after another established new records of "farthest North." The names of Nansen, the Duke of the Abruzzi, and Peary, became familiar to a generation whose imagination seemed curiously in sympathy with that lure of the North which determined the life activities of so many would-be discoverers. So when in the early Autumn of 1909 it was suddenly announced that two explorers in succession had at last, in the picturesque phrasing of one of them, "penetrated the Boreal Center and plucked the polar prize," the popular mind was stirred as it has seldom been by any other event not having either a directly personal or an international political significance.

The two men whose claims to have discovered the pole were thus announced in such spectacular fashion, were Dr. Frederick A. Cook, of Brooklyn, and Lieutenant Commander Robert E. Peary, of the United States Navy. Dr. Cook claimed to have reached the pole, accompanied only by two Eskimo companions, on the twenty-first day of April, 1908. Commander Peary reported that he had reached the pole, accompanied by Mr. Matthew H. Henson and four Eskimos, on the seventh day of April, 1909.

The controversy that ensued regarding the authenticity of these alleged discoveries is not likely to be forgotten by any reader of our generation. Its merits and demerits have no particular concern for the purely scientific inquirer. At best, as Professor Pickering of Harvard is reported to have said, "the quest of the pole is a good sporting event" rather than an enterprise of great scientific significance. It suffices for our present purpose, therefore, to know that Dr. Cook's records, as adjudged by the tribunal of the University of Copenhagen, to which they were sent, were pronounced inadequate to demonstrate the validity of his claim; whereas Peary and Henson were adjudged by the American Geographical Society, after inspection of the records, to have accomplished what was claimed for them. What has greater interest from the present standpoint is the question, which the controversy brought actively to the minds of the unscientific public, as to how tests are made which determine, in the mind of the explorer himself, the fact of his arrival at the pole.

The question has, indeed, been largely answered in the earlier pages of this chapter, in our discussion of the sextant and the _Nautical Almanac_; for these constitute the essential equipment of the arctic explorer no less than of the navigators of the seas of more accessible latitudes. There is one important matter of detail, however, that remains to be noted. This relates to the manner of using the sextant. On the ocean, as we have seen, the navigator levels the instrument at the visible horizon; but it is obvious that on land or on the irregular ice fields of the arctic seas no visible horizon can be depended upon as a basis for measuring the altitude of sun or stars. So an artificial horizon must be supplied.

The problem is solved by the use of a reflecting surface, which may consist of an ordinary mirror or a dish of mercury. The glass reflector must be adjusted in the horizontal plane with the aid of spirit levels; mercury, on the other hand, being liquid, presents a horizontal surface under the action of gravitation. Unfortunately mercury freezes at about 39 degrees below zero; it is therefore often necessary for the arctic explorer to melt it with a spirit lamp before he can make use of it. These, however, are details aside from which the principles of use of glass and mercury horizon are identical. The method consists simply in viewing the reflected image of the celestial body--which in practice in the arctic regions is usually the sun--and so adjusting the sextant that the direct image coincides with the reflected one. The angle thus measured will represent twice the angular elevation of the body in question above the horizon,--this being, as we have seen, the information which the user of the sextant desires.

Of course the explorer makes his "dash for the pole" in a season when the sun is perpetually above the horizon. As he approaches the pole the course of the sun becomes apparently more and more nearly circular, departing less and less from the same altitude. Hence it becomes increasingly difficult to determine by observation the exact time when the sun is at its highest point. But it becomes less and less important to do so as the actual proximity of the pole is approached; and as viewed from the pole itself the sun, circling a practically uniform course, varies its height in the course of twenty-four hours only by the trifling amount which represents its climb toward the summer solstice. Such being the case, an altitude observation of the sun may be made by an observer at the pole at any hour of the day with equal facility, and it is only necessary for him to know from his chronometer the day of the month in order that he may determine from the _Nautical Almanac_ whether the observation really places him at ninety degrees of latitude. Nor indeed is it necessary that he should know the exact day provided he can make a series of observations at intervals of an hour or two. For if these successive observations reveal the sun at the same altitude, it requires no _Almanac_ and absolutely no calculation of any kind to tell him that his location is that of the pole.

The observation might indeed be made with a fair degree of accuracy without the use of the sextant or of any astronomical equivalent more elaborate than, let us say, an ordinary lead pencil. It is only necessary to push the point of the pencil into a level surface of ice or snow and leave it standing there in a vertical position. If, then, the shadow cast by the pencil is noted from time to time, it will be observed that its length is always the same; that, in other words, the end of the shadow as it moves slowly about with the sun describes a circle in the course of twenty-four hours. If the atmospheric conditions had remained uniform, so that there was no variation in the amount of refraction to which the sun's rays were subjected, the circle thus described would be almost perfect, and would in itself afford a demonstration that would appeal to the least scientific of observers.

An even more simple demonstration might be made by having an Eskimo stand in a particular spot and marking the length of his shadow as cast on a level stretch of ice or snow. Just twelve hours later let the Eskimo stand at the point where a mark had been made to indicate the end of the shadow, and it would be found that his present shadow--cast now, of course, in the opposite direction--would reach exactly to the point where he had previously stood. The only difficulty about this simple experiment would result from the fact that the sun is never very high as viewed from the pole and therefore the shadow would necessarily be long. It might therefore be difficult to find a level area of sufficient extent on the rough polar sea. In that case another measurement similar in principle could be made by placing a pole upright in the snow or ice and marking on the pole the point indicated by the shadow of an Eskimo standing at any convenient distance away. At any interval thereafter, say six or twelve hours, repeat the experiment, letting the man stand at the same distance from the pole as before, and his shadow will be seen to reach to the same mark.

Various other simple experiments of similar character may be devised, any of which would appeal to the most untutored intelligence as exhibiting phenomena of an unusual character. Absolutely simple as these experiments are, they are also, within the limits of their accuracy, absolutely demonstrative. There are only two places on the globe where the shadow of the upright pencil would describe a circle, or where the man's shadow would be of the same length at intervals of twelve hours, or would reach to the same height on a pole in successive hours. These two regions are of course the poles of the earth. It may reasonably be expected that explorers who reach the poles will make some such experiments as these for the satisfaction of their untrained associates, to whom the records of the sextant would be enigmatical. But for that matter even an Eskimo could make for himself a measurement by using only a bit of a stick held at arm's length--as an artist measures the length of an object with his pencil--that would enable him to make reasonably sure that the sun was at the same elevation throughout the day--subject, however, to the qualification that the polar ice was sufficiently level to provide a reasonably uniform horizon.

While, therefore, it appears that the one place of all others at which it would be exceedingly easy to determine one's position from the observation of the sun is the region of the pole, it must be borne in mind that the low elevation of the sun, and the extreme cold may make accurate instrumental observations difficult; and it is conceivable that the explorer who had the misfortune to encounter cloudy weather, and who therefore gained only a brief view of the sun, might be left in doubt as to whether he had really reached the goal of his ambition. Fortunately, however, the explorers who thus far claim to have reached the pole record uninterruptedly fair weather, enabling observations to be taken hour after hour. Under these circumstances, there could be no possibility of mistake as to the general location, although perhaps no observation, under the existing conditions, could make sure of locating the precise position of the pole within a few miles.

A curious anomaly incident to the unique geographical location of the pole is that to the observer stationed there all directions are directly south. Yet of course all directions are not one, and the query may arise as to how an explorer who has reached the pole may know in what direction to start on his return voyage. The answer is supplied by the compass, which--perforce pointing straight south--indicates the position of the magnetic pole and so makes clear in which direction lies the coast of Labrador. Moreover if the explorer is provided with reliable chronometers, which of course record the time at a given meridian--say that of Greenwich--these will enable him to determine by the simplest calculation what particular region lies directly beneath the sun at any given time. If, for example, his chronometer shows five o'clock Greenwich time, he knows that the sun's position, as observed at the moment, marks the meridian five hours (_i.e._, 75° of longitude) west of Greenwich.

While the arctic region appears thus to have given up its last secret, this is not as yet true of the antarctic. The expedition of Lieutenant (now Sir Ernest) Shackleton, in 1908, approached within about one hundred and eleven miles of the South Pole. The intervening space--less than two degrees in extent--represents, therefore, the only stretch of latitude on the earth's surface that has not been trodden by man's foot or crossed by his ships. More than one expedition is being planned to explore this last remaining stronghold, and in all probability not many years--perhaps not many months--will elapse before the little stretch of ice that separated Lieutenant Shackleton from the South Pole will be crossed, and man's conquest of the zones will be complete.

II

THE HIGHWAY OF THE WATERS

There is no doubt that the use of sails for propelling boats is as old as civilization itself. We know that the Egyptians used sails at least 4,000 years before the Christian era. They did not depend entirely upon the sails, however, but used oars in combination with them. Steering was done with single or double oars lashed to the stern and controlled by ropes or levers. This method of steering remained in use until late in the Middle Ages, the invention of the rudder being one of the few nautical inventions made during the centuries immediately following that unproductive period of history known as the Dark Age.

Following the Egyptians, the Phœnicians were the greatest maritime nation of ancient times, but unfortunately they have left no very satisfactory and authentic records describing their boats. In all probability, however, their ships were galleys having one or two banks of oars, fitted with sails similar to those of the Egyptians.

If our knowledge of Phœnician boats is meager, our knowledge of Greek boats, particularly the fighting craft, is correspondingly full. From the nature of its geographical location Greece was necessarily a maritime nation, and it was here that boat-building reached a very high state of development during the period of Greek predominance. Large ships fitted with sails and having several banks of rowers were used habitually in commerce and war, and it was here also that the management of sails became so well understood that oars were often dispensed with except as auxiliaries.

It was in Greece that the custom of having several banks of oars superimposed reached its highest development, but the fabulous number of such banks credited by some authors seems to be entirely without foundation. It is possible that as many as seven banks were used, although the evidence in favor of more than five is very slight.

The writings of Callixenos describe a ship said to have been used by Ptolemy Philopater, which was a forty-banker. This ship is described as 450 feet long, 57 feet broad, carrying a crew of about 7,000 men, of whom 4,000 were rowers. This description need not be taken seriously, as there is no proof that boats of such proportions were ever attempted in ancient times. But it is certain that the Greeks did build large vessels, some of them at least one hundred and fifty feet long--perhaps even larger than this. The tendency of shipbuilders during the later Greek period was to build large, unwieldy boats, which used sails under favorable circumstances, but depended entirely upon oars for manœuvering in battle.

The Romans used similar vessels of large size until the time of the battle of Actium, where the clumsy, many-banked ships of Antony and Cleopatra were destroyed by the lighter single- or double-banked vessels of Augustus. Augustus had adopted the low, swift, handy vessels of a piratical people, the Liburni, who had learned in their sea fights against all kinds of vessels that the lighter type of boat could be used most effectively. Structurally the hulls of these boats were not unlike modern wooden vessels.

While the various types of vessels were being developed in the Mediterranean region, a race of mariners far to the north were perfecting boats in which they were destined to overrun the Western seas from the tropics to the arctic circle. These people, the Norsemen, left few written descriptions that give a good idea of the construction of their boats, which were sufficiently seaworthy to enable the Danes to cross the Atlantic and colonize America. But thanks to one of their peculiar burial customs some of their smaller boats have been preserved and brought to light in recent years. It was their custom when a great chief died, to bury him in a ship, heaping earth over it to form a great mound. In most instances the wood of such boats, buried for a thousand years, has entirely disappeared; but in some mounds the boats have been preserved almost intact.

From the specimens so preserved it is known that the Norsemen knew how to shape the hulls of their boats almost as well as the modern boat-builder. This fact is interesting because the immediate successors of the Norsemen, either through ignorance or choice, reverted to most primitive types in building their boats. Thus it required centuries for them to develop a knowledge of hull-construction that was familiar in ancient times to the northern rovers. Scandinavia itself never entirely forgot the art, and there are boats built in Norway to-day closely similar in all essentials to some of the boats constructed by the Norsemen.

MEDIÆVAL SHIPS

The contrast in shape and construction between the trim ships of the Norsemen and the short, top-heavy vessels which were the approved European type during the early Middle Ages, is most striking. The Mediæval shipbuilders in striving to improve their craft, making them as seaworthy and as spacious as possible, first added decks, and then built towering superstructures at bow and stern. The result was a vessel which would have been so top-heavy that it would be likely to capsize had it not been so broad that "turning turtle" was out of the question.

It was in such ships that Columbus made his voyage of discovery in 1492, although the superstructures fore and aft on his boat were less exaggerated than in some later vessels. Nevertheless they were veritable "tubs"; and we know from the experience of the crew that sailed the replica of the _Santa Maria_ across the ocean in 1893, that they were anything but comfortable craft for ocean traveling.

This replica of the _Santa Maria_ was reproduced with great fidelity by the Spanish shipbuilders, and, manned by a Spanish crew, crossed the ocean on a course exactly following that taken by Columbus on his first voyage. Sir George Holmes' terse description of this voyage is sufficiently illuminating without elaboration. "The time occupied was thirty-six days," he says; "and the maximum speed attained was about 6½ knots. The vessel pitched horribly!"

Two full centuries before the discovery of America the rudder had been invented. There is no record to show who was responsible for this innovation, although its superiority over the older steering appliances must have been appreciated fully. But after the beginning of the fourteenth century the rudder seems to have come into general use, entirely supplanting the older side-rudder, or clavus.

MODERN SAILING SHIPS

For a full century after the voyage of Columbus little progress was made in ship construction; short, stocky boats, with many decks high above the water-line at bow and stem continuing to be the most popular type. In the opening years of the seventeenth century, however, the English naval architect, Phineas Pett, departed from many of the accepted standards of his time, and produced ships not unlike modern full-rigged sailing vessels, except that the stern was still considerably elevated, and the bow of peculiar construction. One of Pett's ships, _The Sovereign of the Seas_, was a vessel 167 feet long, with 48 foot beam, and of 1,683 tons burthen. The introduction of this type of vessel was a distinct step forward toward modern shipbuilding.

The replica of Henry Hudson's famous _Half Moon_, a typical fighting ship of the 16th century, and a modern submarine. The photograph was taken in New York Harbor during the Hudson-Fulton celebration, September, 1909.]

The tendency of shipbuilders during the eighteenth century was to increase the length of vessels in proportion to the breadth of beam and diminish the depth of the hull and superstructures, above the water line, with improved sailing qualities. England's extensive trade with India and the far East was conducive to this development, as the "East Indiamen" were necessarily a combination of merchant vessel and battleship.

In the first half of the nineteenth century America rose to great commercial importance thanks to her fleets of fine sailing vessels. Speed rather than strength in their ships was the aim of American ship-builders, to gain which they built boats proportionately longer and narrower than ever constructed before for ocean traffic. The culminating type of wooden sailing ship was represented by the "Baltimore clippers," in which the length was five, and even six, times the beam, with light rigging and improved mechanical devices for handling it, whereby the amount of manual labor was greatly lessened. One of these ships, the _Great Republic_, built in 1853, was over three hundred feet long, and 3,400 tons register. She was a four-masted vessel, fitted with double topsails, with a spread of canvas about 4,500 square yards.

The modern descendant of the wooden clipper ship is the schooner with from four to six masts. Some of these vessels exceed the older boats in size and carrying capacity, if not in speed. Perhaps the largest schooner ever constructed is the _Wyoming_, which was completed at Bath, Maine, early in the year 1910. This vessel is 329 feet long and 50 feet broad. It has a carrying capacity of 6,000 tons. The construction of such a vessel at so recent a period suggests that the day of the sailing ship is by no means over notwithstanding that a full century has elapsed since the coming of the steamboat. Here, as so often elsewhere in the history of progress, it has happened that the full development of a type has not been reached until the ultimate doom of that type, except for special purposes, had been irrevocably sealed. Ever since the full development of the steamboat in the early decades of the nineteenth century, the sailing ship has seemed almost an anachronism; and yet, in point of fact, the steamship did not at once outrival its more primitive forerunner. Even in the matter of speed, the sailing ship more than held its own for a generation or so after the steamship had been placed in commission. In 1851 the American clipper _Flying Cloud_ made 427 knots in twenty-four hours; and _The Sovereign of the Seas_ bettered this by averaging over eighteen miles an hour for twenty-four consecutive hours. The Atlantic record for sailing vessels is usually said to have been made in 1862 by the clipper ship _Dreadnought_ in a passage between Queenstown and New York, the time of which is stated as nine days and seventeen hours. It should be remarked, however, that the authenticity of this extraordinary performance has been challenged.

Be that as it may, it is certain that the speediest sailing ships, granted favorable conditions of wind and wave, more than surpassed the best efforts of the steamship until about the closing decades of the nineteenth century. But of course long before this the steamship had proved its supremacy under all ordinary conditions. Even though sailing ships continued to be constructed in large numbers, their picturesque rigging became less and less a feature in all navigable waters, and the belching funnel of the steamship had become a characteristic substitute as typifying the sea-going vessel.

The story of the development of this new queen of the waters must now demand our attention. It begins with the futile efforts of several more or less visionary enthusiasts who were contemporaries of James Watt, and who thought they saw great possibilities in the steam engine as a motive power to take the place of oars and sails for the propulsion of ships.

EARLY ATTEMPTS TO INVENT A STEAMBOAT

Among the first of these was an American named John Fitch. Judged by the practical results of his efforts, he was not a highly successful inventor; as a prophet, however, and as an experimenter whose efforts fell just short of attainment, he deserves a conspicuous place in the history of an epoch-making discovery. Yet his prophecy was based on his failures. From 1780, for twenty years he strove to perfect a steamboat. His efforts did not carry him far beyond the experimental stage. But his courage and enthusiasm never waned. "Whether I bring the steamboat to perfection or not," he declared, "it will some time in the future be the mode of crossing the Atlantic for packets and armed vessels."

At that very time Benjamin Franklin said this would never be. But twenty years later Fulton's _Clermont_ paddled up the Hudson River from New York to Albany and opened the era that saw Fitch's prophecy fulfilled. This was in 1807--a year that must stand as the most momentous in maritime history. In that year the little _Clermont_ steamed slowly from New York to Albany, a distance of one hundred and fifty miles in thirty-two hours, unaided by sails or oars, and propelled entirely by steam-power. A sail-boat could cover the distance in the same number of hours; a modern torpedo boat in one-sixth the time. Yet no performance of any boat, before or since, had such far-reaching effects upon the progress of the world.

When Fulton turned his attention from his favorite theme--the invention of a submarine boat--and took up the question of perfecting a boat propelled by steam, he did not find himself the first or the only inventor in the field. For a hundred years, in round numbers, men had been wrestling with the question of applying steam pressure to boat propulsion. All manner of more or less ingenious devices had been conceived, most of them having a germ of success in the principles involved, but all of them being failures in actual practice.

Among the most promising of these first steamboats were those in which the propeller, or the paddle-wheel, was tried; but neither of these methods was looked upon favorably at first. Less promising was one in which the motive power was a jet of water pumped through a submerged tube--a principle that still periodically fascinates certain modern inventors.

The small figure in the centre represents a very remarkable steamboat constructed in America by John Fitch. The precise date of its construction is not clearly established, but the inventor had made efforts at steam navigation as early as 1776. The upper figure shows a marine engine made in Scotland in 1788 for Patrick Miller by William Symington. It was used to equip a double-hulled pleasure boat which it is said to have propelled at the rate of five miles an hour. The motive power is supplied by two open-top Newcomen cylinders. The lower figure represents a modern side wheel steamer with oscillating engines.]

But the boats that seemed to have come nearer attaining practical success for the moment were those in which several sets of oars worked by steam were placed vertically on each side of the hull, the machinery so arranged that the oars were dipped into the water and drawn sternward by one motion of the machinery, raised and carried toward the bow by the opposite motion. In some of these boats it was planned to have four sets of oars, two sets on each side, which were to work alternately, so that while one set was traveling forward through the air, its mate would be paddling through the water, thus insuring a continuous forward impulse. But the machinery for these boats proved to be too cumbersome and complicated for practical results, and this idea was finally abandoned. The jet of water did not prove any more successful, and but two other methods were available--the propeller and the paddle-wheel.

Both of these methods of utilizing the power of moving water had been familiar in the form of the Archimedian screw and the commonplace overshot or undershot mill-wheel. In these examples, of course, the force of the water was used to move machinery, reversing the action of the paddle-wheel of the boat. And yet the principles were identical. Obviously if the conditions were reversed, and the undershot mill-wheel, for example, forced against the water with corresponding power, the propulsive effect might be great enough--since action and reaction are equal--to move a boat of considerable size. But curiously enough, at the time when Fulton began his experiments there was a wave of general belief that when this principle was applied to boats it would fail. The reason for this lay in the fact that several such boats had been built from time to time, and all had failed. The fault, of course, lay in some other place than in their paddle wheels; but for the time being the wheel, and not the machinery, was shouldered with the blame.

Just a hundred years before Fulton finally produced his practical paddle-wheel steamboat, a prototype was built by the Spaniard, Blasco de Gary. In 1707, this inventor constructed a model paddle-wheel steamboat, and tried it upon the river Fulda. But this model boat failed to work, and the experiment was soon forgotten.

Twenty-five years later Jonathan Hulls of England patented a marine engine which he proposed to use in a boat which was to be propelled by a stern wheel. His idea was to use his boats as tug- or tow-boats, and to equip the larger vessels themselves with steam. But his engines were defective and his boats did not achieve commercial success.

During the time of the American Revolution, a French inventor, the Marquis de Jouffroy, made several interesting experiments with steam-propelled boats, using the principle of the paddle which was dipped and raised alternately as referred to a few pages back. His boats made several public trials, one of them ascending the Seine against the current; but nevertheless, the French government refused to grant the inventor a patent. Presumably, therefore, the boat was not considered a practical success in official circles; and this view is tacitly conceded by the fact that no more boats of its type were constructed. Had they been really practical steamboats it is a fair presumption that others would have been constructed and put into operation, regardless of patents. Nevertheless, in France to-day, the Marquis de Jouffroy is often referred to as the father of steam navigation.

The idea of propelling a boat by means of a jet of water pumped out at the stern by steam pumps was given a practical test in 1784, by James Rumsey. His boat made a trial trip on the Potomac River in September of that year, General Washington and other army officers being present on this occasion. The boat was able to make fairly good progress through the water, and seemed so promising that a company was formed by capitalists known as the Rumsey Society, for promoting the idea and building more boats. Rumsey was sent to England where he undertook the construction of another boat, meanwhile taking out patents in Great Britain, France, and Holland. Before his boat was completed, however, he died suddenly, and the Rumsey Society passed out of existence shortly afterwards.

An even closer approach to practical success was made in Scotland by James Symington, who in 1788, in association with two other Scotchmen, Miller and Taylor, constructed a boat consisting of two hulls, with a paddle-wheel between them worked by a steam-engine. This boat worked so well that in 1801, Lord Dundas engaged Symington to build a smaller boat to be used for towing on the Caledonian Canal. This boat, called the _Charlotte Dundas_, completed in 1802, is said to have been capable of towing a vessel of one hundred and forty tons "nearly four miles an hour." But in doing this the resulting "wash" so threatened the banks of the canal that the vessel was laid up and finally rotted and fell to pieces.

By many impartial judges this boat is considered the first practical steamboat, and its failure to establish its claim due to the force of circumstances rather than to any inherent defects. Symington was too poor to pursue his work independently, and was deterred by the attitude of James Watt, who "predicted the failure of his engine, and threatened him with legal penalties if it succeeded." And when at last he received an order for eight smaller vessels from the Duke of Bridgewater, his patron died before the details of the agreement had been completed. So that while he failed in accomplishing what was done by Fulton a few years later, it is certain that, as Woodcraft says, "He combined for the first time those improvements which constitute the present system of steam navigation."

Some of Symington's engines have been preserved, and one of them is now in the Patent Office Museum in London. Since the beginning of practical steam navigation this engine has been tested several times, the result showing that Woodcraft's estimate is not overdrawn.

While Symington was thus perfecting a paddle-boat, an American, Col. John Stevens of Hoboken, New Jersey, was on the verge of accomplishing the same end with a screw-propeller boat--a form of steamship that did not come into use until some forty years later.

The "Charlotte Dundas" (lower figure) was built in 1801 by A. Hart at Grangemouth, Scotland, and engined by William Symington, for service on the Forth and Clyde Canal. Its length was 56 feet; beam 18 feet; depth 8 feet. The boat was a practical success, but its use was discontinued because of the damage done to the banks of the Canal by the wash of the paddles. The upper left-hand figure is a picture of Fulton's "Clermont." The diagram at the right represents the "Clermont's" paddle wheels and the mechanism by which they were worked.]

Stevens also invented what he called a "rotary engine" which was really an engine constructed on the same principle as the modern turbine engine. It was a small affair which he placed in a skiff, and used for turning the screw-propeller of a boat which was able to travel at a rate of three or four miles an hour on the North River, during the fall of 1802. But Stevens found so much difficulty in packing the blades of this engine without causing too much friction that he finally abandoned it for the more common type of reciprocating engine. But if this little steamboat had its defects, it nevertheless contained the germs of two great features of steam navigation--the screw propeller and the turbine engine, the advantage of the first of which was not recognized for nearly half a century, and the other not until almost a full century later.